This problem can occur if one of the following conditions is true:
The default security provider in Windows XP has changed.
The system drive letter has changed.
To work around this problem, use the appropriate method.
Reset the default security provider in Windows XP
To reset the default security provider in Windows XP, delete the relevant registry keys from the registry. To do this, follow these steps:
Start the computer. Press the F8 key during startup to start the computer in safe mode.
Click Start, click Run, type regedit, and then click OK.
Delete the following registry subkeys from the registry:
HKEY_USERS\.DEFAULT\Software\Microsoft\Cryptography\Providers
HKEY_USERS\S-1-5-20\Software\Microsoft\Cryptography\Providers
Exit Registry Editor.
Restart the computer.
Reset the drive letter of the system drive
Use Registry Editor to change the drive letter of the system drive back to its original value. Edit the following registry key to change the value of the system drive:
HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices
For more information about how to restore the system drive letter, click the following article number to view the article in the Microsoft Knowledge Base:
223188 How to restore the system/boot drive letter in Windows